Boat construction



. 1,947- A. G. s. SANDISON 2,413,787

BOAT CONSTRUCTION Filed June 20, 1945 2' Sheets-Sheet 1 Jan. 7, 19.47. s so 2,413,787

BOAT CONSTRUCTION Filed June 20, 1945 2 Sheets-Sheet 2 1r 11/ Z I I 0 J x L, fl 3.

Patented Jan. 7, 1947 BOAT CONSTRUCTION Alexander Greswolde Seymour Sandison, Brantford, Ontario, Canada Application June 20, 1945, Serial No. 600,549 In Canada September 12, 1944 11 Claims.

This invention relates to boat construction, and particularly to the construction of wooden boats of round bilged type, and has for its object to provide such a method of construction for the ribs, timbers or frames of a boat that machine operations may be used largely in place of the usual construct on methods, whereby the amount of labour required for construction may be reduced, and where y also the quality of work and the accuracy of fitting may be improved over that usually obtained. I

As ordinarily constructed the wooden frames of a boat are usually either of bent or of cut type. Bent frames are usually of'hardwood, such as oak or elm, and are usually formed by softening the wood by steaming and then bend ng to shape. Such frames, however, as ordinarily made suffer from the disadvantage that they are necessarily of small sectional dimensions to permit bending without breakage and their rigidity is insufiicient to prevent the planking of the'boat becoming highly stressed in service with a possibility of distortion of the shape of the boat or damage to fastenings in course of time, and the liability to distortion is enhanced by a tendency of the bent frames to straighten. Cut frames, which are usually built up of jointed segments, sometimes referred to as cleats or 'futtocks, can readily be made of sufficiently heavy section to prevent danger of serious stressing or distortion of the planking, but, as ordinarily made, are subject to the disadvantage that'they involve a laborious process of marking off, cutting and fitting, resulting in high cost of construction if work of first class strength and accuracy of fit is required.

The present invention is concerned primarily with the construction of boats having cut frames longitudinally spaced and having their skins composed of bent longitudinal strakes which are initially fabricated as unbent strakes, and in the present invention the frames are initially formed as a plurality of segments, these segments being located and held in their designed positions relative to the unbent strakes and cut to shape while so held. It is preferred to form the segments of such length that each segment has an effective span equivalent to the width of two strakes, and to cut the ends of the segments with tenons or other matching means of registration whereby assembly may be facilitated and secure joints made between the ends of the frame segments on assembly. For preference the joints should be staggered so that joints in adjacentframes do not occur opposite the same strake.

2 By the use of this invention it is possible to employ certain machine methods in shaping the frame segments and thereby to ensure rapid production and accurate fitting, rendering it easy to produce frames of satisfactory strength and accuracy of jointing. The invention is particularly applicable with a method of boat construction described in a previous patent application by the present inventor entitled Improvements in boat construction, application Serial No. 550,- 741 filed August 23, 1944, which issued March. 19, 1946 a Patent No. 2,397,049 and using a machine of type described in another previous patent application by the present inventor'entitled A machine for fabricating strakes for boat construction or the like, application Serial NO.550,738 filed August 23, 1944, for the shapingof the segments; and in the following description it is assumed that the machine and the methods of boat construction described in the abovementioned patent applications are employed.

In describing the invention reference will be made to the attached diagrammatic drawings, which illustrate the preferred form of the invention, and in which:

Fig. 1 shows four separated strakes with frame segments'attached thereto.

Fig. 2 shows the assemblyof the set of strakes and frame segments shown in Fig. -1.

Fig. 3 is a diagram illustrating the longitudinal shaping of a strake with attached frame segments.

Fig. 4 is a diagram on an enlarged scale'illustrating the transverse shaping cf-a strake with attached frame segments.

Fig. '5 shows a method of forming the ends of the frame segments, this method differing from that shown in'the preceding figures.

Fig. 6 shows another method of forming the ends of the frame segments. f

Fig. '7 is a transverse section of a boat showing the complete assembly of a frame.

In the drawings similar parts are indicated by like reference numerals.

Referring to Fig. l, strakes I, pre-fabricated prior to their assembly to form part of the skin of a boat, have frame segments 2 secured to them, which segments are cut with tongues or tenons 3, and with grooves 4-, the tongues and grooves being designed to register on assembly. The number of segments on each strake is equal to half the designed number of frames andfth'e longitudinal positions of the fra'mesegments on adjacent strakes are staggered.--

- In Fig. 2 the set of strakes illustrated in Fig. 1

is shown assembled to form part of the skin of a boat. The strakes have been bent longitudinally and assembled in such a manner that the edges of the strakes lie together, the tenons and grooves at the ends of the frame segments bein also in registration. It will be understood that on assembly the ends of the frame segments may additionally be secured to one another and to the adjoining strakes by gluing, or by screws, nails or through fastenings, or by a combination'of these methods, such methods being well known.

The preferred shape of the strake is illustrated with reference to Fig. 3, which shows reference axes OX and OY, the axis OX corresponding to the centre line of the strake if the latter is symmetrical. Dimension it corresponds to the longitudinal distance from the. arbitrary origin and dimension y corresponds to the distance from the line O-X to the edge of the strake, as measured across the inner surface of the strake, and dimension 1 corresponds to the distance from the line OX to a reference point located at or near the end of the frame segment. The

reference point to which 1/ is measured corresponds to the position of the axis line of the adjacent strake on assembly and does not necessarily correspond to an actual point on the joint between the ends of the frame segments. A described in, the above-mentioned previous patent applications the edge of the strake may be cut in substantial accordance with the formula where A, B, C, D and E are constants. The ends of the frame segments are cut so that dimension y is slightly less than 2y, the theoretical relationship for correct registration being given in the next paragraph.

In the cross section illustrated in Fig. 4 dimensions y and 1 have the same meaninigs as described with reference to Fig. 3, and the angle a is the theoretical angle of bevel of the edge of the planking at that particular section, being such as would secure exact contacts between the edges of adjacent strakes on assembly. The faying surface 5 of the frame segment is cut at an angle equal to with respect to the surface of the strake, as is shown, and the tenoning and grooving of the ends of the frame segment is cut at an angle equal to 2a with respect to a line perpendicular to the strake surface, as is shown. The correct value of dimension y may be shown to be equal to y(l+cos 2oz) In the operation of fabricating the strakes with the attached frame segments a sequence of operations such as the following may be employed. Firstly, pieces of Wood of suitable section and of length somewhat greater than the finished dimensions of the frame segments are secured at the required intervals to the plank from which the strake is to be cut. Secondly, the strake with its attached frame segments is mounted on the machine, which is set in accordance with the required value of width y and angle 0:, and the edges of the strake are then cut. Thirdly, the machine is set to cut in accordance with width y but at an angle equal to 20:, and the faying surfaces of the frame segments are then cut. Fourthly, the machine is set to cut in accordance with a nominal width equal to y and for an angle equal to 20:, and the jointing surfaces at the ends of the frame segments are then cut.

Forms of joint for the frame ends other than the longitudinal tenoning shown in Figs. 1 to 4 inclusive are exemplified in Figs. 5 and 6. In Fig. 5 a method of transverse tenoning or matching is employed, the segment I 2 being formed with a transverse tenon [3 at one end and a transverse groove M at the other end, and also with a faying surface l5. In Fig. 6 cylindrically formed registering surfaces are employed and the segment 22 has a faying surface 25 and is formed with a pin 25 at one end and a hole 21 at the other end. The properties of these various types of joints are not identical and the choice of type may be made according to preference. Thus the longitudinal tenoning method shown in Figs. 1 to 4 gives positive location of the strakes on assembly as to their relative transverse position, but not as to their relative longitudinal positions; the transverse tenoning method shown in Fig. 5 gives positive location of the strakes on assembly as to their relative longitudinal positions but not as to their relative transverse positions; while the concentric registration method shown in Fig. 6 gives positive location of the strakes on assembly both as regards their rela tive longitudinal and relative transverse positions.

In the description hitherto it has been as sumed that the adjoining profiles of adjacent strakes are of symmetrical contour, that is to say that the one profile forms a mirror image of the other, and for reasons of simplicity it is generally preferred to adopt such symmetry between the adjoining profiles. It will, however, be evident that this symmetry is not essential to the operation of the invention, though departure therefrom generally tends to complicate the settings for the machine without any real advantage being secured.

The final assembly of a frame when the assembly of a boat is completed is illustrated in Fig. 7. The two halves of the complete frame are here shown joined by a floor 8 which in turn is secured to the keel 9. In the example shown the frame is straight over some portion of its length and where such straight portions occur the frame may be made Without joints, and the corresponding straight frame segments need not then necessarily be cut to shape in conjunction with the strakes.

In the method of construction described, the lengths of the frame segments in curved portions of the frame are made to correspond to a span equivalent to the width of two strakes, and in most cases this is preferable. It is, however, within the scope of the invention to construct the segments'so as to span only the width of one strake, or so as to span three or more strakes, and machine settings can readily be devised to cut the egments accordingly.

I claim:

1. In the process of construction of a boat hav ing longitudinally spaced frames and having its skin composed of bent longitudinal strakes which are initially fabricated as unbent strakes, the initial formation of said frames as a plurality of segments, said segments being located and held in their designed positions relative to said unbent strakes and cut to shape while so held.

2. In the process of construction of a boat having longitudinally spaced frames and having its skin composed of bent longitudinal strakes which are initially fabricated as unbent strakes, the initial formation of said frames as a plurality of segments, said segments being located and held in their designed positions relative to said unbent strakes and cut with matching joint faces while so held.

3. In the process of construction of a boat having longitudinally spaced frames and having its skin composed of bent longitudinal strakes which are initially fabricated as unbent strakes, the initial formation of said frames as a plurality of segments, said segments being located and held in their designed positions relative to said unbent strakes and cut with matching joint faces while so held, said matching joint faces comprising tenons and grooves longitudinally disposed in relation to said strakes.-

4. In the process of construction of a boat having longitudinally spaced frames and having its skin composed of bent longitudinal strakes which are initially fabricated as unbent strakes, the initial formation of said frames as a plurality of segments, said segments being located and held in their designed positions relative to said unbent strakes and cut with matching joint faces while so held, said matching joint faces comprising tenons and grooves transversely disposed in relation to said strakes.

5. In the process of construction of a boat having longitudinally spaced frames and having its skin composed of bent longitudinal strakes which are initially fabricated as unbent strakes, the initial formation of said frames as a plurality of segments, said segments being located and held in their designed positions relative to said unbent strakes and cut with matching joint faces while so held, said matching joint faces comprising cylindrically formed surfaces.

6. In the process of construction of a boat having longitudinally spaced frames and having its skin composed of bent longitudinal strakes which are initially fabricated as unbent strakes, the initial formation of said frames as a plurality of segments of effective length equivalent to the width of two strakes, said segments being located and held in their designed position relative to said unbent strakes and cut to shape while so held.

7. In the process'of construction of a boat having longitudinally spaced frames and having its skin composed of bent longitudinal strakes which are initially fabricated as unbent strakes, the initial formation of said frames as a plurality of segments of effective length equivalent to the width of two strakes, said strakes being located and held in staggered relationship in their designed position relative to said unbent strakes and cut to shape while so held.

8. In the process of construction of a boat having strakes and having frames composed of a plurality of segments, the securing of unfinished frame segments to an unassembled strake, followed by their shaping while so secured.

9. In the process of construction of a boat having strakes, and having frames composed of a plurality of segments, the securing of frame segments having unfinished faying surfaces and ends in position on an unassembled strake having unfinished edges, followed by machining to finished shape of the edges of the strake and of the faying surfaces and ends of the frame segments secured thereto.

10. In the process of construction of a boat having strakes, and having frames composed of a plurality of segments, the securing of frame segments having unfinished faying surfaces and ends in position on an unassembled strake having unfiished edges, followed by machining operations to cut the edges of the strake to their correct width and angle of bevel, to cut the faying surfaces of the frame segments to their correct angle of bevel, and to cut the ends of the frame segments in the form of joint surfaces.

11. In the process of construction of a boat having strakes, and having frames composed of a plurality of segments, the securing of frame segments having unfinished faying surfaces and ends, and Of length sufficient to span the width of two strakes, in position on an unassembled strake having unfinished edges, followed by machining operations to cut the edges of the strake to profile and in accordance with a required angle of bevel, to cut the faying surfaces of the frame segments to an angle equal to twice said angle of bevel, and to cut the ends of the frame segments in the form of joint surfaces.

ALEXANDER GRESWOLDE SEYMOUR SANDISON. 

